/**
  * @return GrantType
  */
 public function getGrantType()
 {
     return GrantType::CLIENT_CREDENTIALS();
 }
 /**
  * @return GrantType
  */
 public function getGrantType()
 {
     return GrantType::REFRESH_TOKEN();
 }
 /**
  * @return GrantType
  */
 public function getGrantType()
 {
     return GrantType::PASSWORD();
 }
 /**
  * @return GrantType
  */
 public function getGrantType()
 {
     return GrantType::AUTHORIZATION_CODE();
 }